Leather-stretching device.



Patented A r. I5, 1902.

J CALDWELL. LEATHER STBETGHING DEVICE.

(Application Med Jan. 16, 1900.)

2 Shuts-Shut I.

(No Model.)

' 2? 30 f2 ELLEIE 26 [nae/2Z0?" Jain UaZaweZZ No. 697,443. v Patented Apr. l5, I902. .1. CALDWELL. v LEATHER STBETCHING DEVICE.-

(Applicntion filed Jan. 16, 1900.)

(lo Modal.) w 2 Sheets-Sheet 2.

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r kals' fllfalrlzey UNITED STATEs PATENT OFFICE.

JOHN CALDWELL, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THE IV. S. NOTT COMPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION.

LEATHER-STRETOHING DEVICE.

SPECIFICATION forming part of Letters Patent No. 697,443, dated April 15, 1902. Application filed January 15, 1900. Serial No. 1,424. (No model.)

Minnesota, have invented certain new and useful Improvements in Leather-Stretching Devices, of which the following is a specification.

My invention relates to apparatus for stretching skins or hides, and especially to the means employed in stretching the divisions of leather commonly known as sides, backs, butts, &c., for use in the manufacture of belting.

The common practice in the preparation of leather for belting is to sever the hides transversely at the shoulder, trim the sides to straighten the edges, and cut the butts longitudinally into sides and backs or other divisions of desired widths, but leaving the rump ends of irregular shape. For holding such divisions during theoperation of stretching the common practice is to clamp the ends to the proper members of a stretching-machine by means of clamps that extend in straight courses entirely across the leather, and in order to prevent the slipping of the leather in the clamps under strong tension it is found necessary to provide their contactsurfaces with ribs or other irrgularities, with the result of producing corresponding creases or irregularities in the clamped portions of the leather, which portions are generally unfit for use in the manufacture of belting and are cut off. 'When the rump or other irregular ends are thus clamped across the body of the leather back of the irregularities of contour, considerable valuable leather becomes Waste; but whether clamps or other means were employed it has uniformly been the practice, so far as I am aware, to stretch the firmer and less-yielding portions to the same degree or extent as the softer and less-firm portions. The result of such operation usually is that the firmer portions (those nearer the middle of the hide) are stretched too much and the softer portions (those nearer the outer edges ofthe hide) are not stretched enough, and such stretching does not serve to remove the warp or twist or buckle that has been produced by the preliminary process of wetting, greasing, and partly drying the leather.

' The principal object of my invention is to provide a series of independent holders adapted to severally engage only relatively short marginal portions of the leather and freely pivoted to a corresponding series of coupling devices that are adjustable upon a stretcherhead and capable of independent and successive connection therewith, whereby the proportion of Waste material may be lessened and the quality'of the body of leather improved by causing its softer and harder portions to be stretched successively and to different degrees, as their variations of fiber may require, to bring all parts to substantially equal hardness in the finished product. Such devices are illustrated in the accompanying drawings, in which-'- Figure 1 isa plan view of a leather-stretching apparatus embodying my improvements and showing a side of leather in place thereon. Fig. 2 is a central vertical longitudinal sectional View, enlarged, of Fig. 1. Fig. 3 is a plan view of the front or right-hand portion of the apparatus shown in Figs. 1 and 2. Figs. L and 5 are respectively plan and vertical sectional views of one of the devices for engaging and holding the leather. Fig. 6 shows a modified construction of such devices; and Figs. 7 and 8 show in perspective and side elevation, respectively, detail views of one of the holders.

In such drawings the frame for supporting the leather-holdin g device is composed of side pieces 1, cross-bars 2, and diagonal braces 3. The fixed and sliding heads, to which the ends of the leather are secured, are designated by A and B, respectively, and the latter is provided with suitable lateral extensions in ways 4., formed in the side bars 1, for guiding its re ciprocatory movements. In use the frame is preferably placed on a table or support 5, with the ends of the sidebars 1 abutting the ends of the frame 6, that supports the operating mechanism. The latter may consist of any of the usualmeans employed in such machines and, as illustrated, may comprise gears 7, a screw 8, revolubly connected to a crosshead 9, and rods 10, carried by the latter and provided with hooks 11 for connecting them to eyes 12, provided on the sliding head B. The operation of the screw in either direct-ion and its stoppage when desired should be under the control of an operator by means of a lever, hand-wheel, or other well-known device, (not shown,) so that the degree of the stretching of the leather may be regulated at will by the operator.

The heads A and B are preferably formed of upper and lower boards 13 and 14, held at front and rear between angular clampingplates 15 and 1G. The lower board 14 is firmly.

held between the vertical portions of the plates by bolts 17, passed through them, and the upper board is securely held in place by the horizontal flange 18 of the outer plate 16 and the upwardly-inclined flange 19 of the inner plate 15, the upper board being shaped to fit the space between such flange and the surface of the lower board. The upper board 13 may be removed when desired by loosening the nuts on the bolts 17 and moving the clamping-plates outward. Bolts 20 extending through the frame sides into or through the boards let hold them firmly in place in the frame and when the bolts are removed the boards rest on lips or flanges 21, extending beneath them from the plates 15 and 16. Backward movement of the head B, when the stress of the draft-rods 10 is relaxed, is prevented by dogs 22, pivoted to ears on the plate 15 of the sliding head, which engage teeth on bars 23, attached to the frame sides 1.

For securing the straight end of a side 0 or other division of a hide to one of the stretcherheads A B the head selected for the purpose is provided with a row of tines or pins 24: on a bar or plate 25, that is secured on the top of the head, the row of tines extending across the head from side to side at right angles to the direction of movement of the slidable head. The straight end of the leather is laid on the tines, so that they will penetrate its margin close to theedge,and it is then pounded with a mallet or other tool to force the tines through it. For securingthe rump or other irregular end of the leather to the other stretcher-head I employ a series of longitudinally and laterally adjustable independent holders, each of which is pivotally connected to a coupling device, with respect to which it may swing laterallyat all times,and is adapted to engage only a short portion of the margin of the leather. These holding devices may consist, as illustrated, of a plate or body 26, having a row of tines or pointed pins 27 for engaging the leather and having in its rear portion a horizontal slot 28 for receiving the end of a bar or coupling device 29 and having also curved slots 30 or openings in its upper and lower walls to receive and guide a pin or roller 31, that projects from the upper and lower surfaces of the bar 29. A pivotal connection is thus formed between the body 26 and the bar 29, whereby either may be turned in horizontal direction to any desired inclination relative to the other, as well while under tension as at other times. The lateral extension of the slots or openings 30 enables a corresponding lateral adjustment of the point of such pivotal connection conformably to the angle of the holder to its coupling-bar to be made, and such adjustment will be eifected automatically when the holder is under tension and its inclination to the coupling device is varied. The bar or shank 29 has its under surface provided with teeth 32 for engaging corresponding serrations 33 on the stretcherhead extending crosswise of the frame. These serrations may be provided on the flange 18 of the plate 16, as indicated in Fig. 2, or on a separate plate 34, secured to the head-board 13, as indicated in Figs. 3, 4, and 5.

In place of the teeth or serrations on the stretcher-head for engaging the holder bars or shanks pins 35 may be provided on the head for entering holes in the holder-bars, as illustrated in Fig. 6, whereby the bars may be pivotally connected to the head. The bars 29 may have rings 36 or handles at their ends for convenience in adjusting them. In applying such devices to the irregular end of a piece of leather the row of pins on each holder may be placed in substantial alinement with the edge of the portion of the margin they are to engage and then driven through the leather, and when all of the holders have been caused to engage the leather all of the coupling-bars may, if desired, be adjusted laterally to positions parallel with the direction of movement of the slidable head and when so adjusted may be connected to the stretcher-head by engagement with its serrations 33 or pins 35. To retain the coupling-bars in place after they have been so connected to the head, a looking or clamping bar 37, hinged to one of the frame sides may be swung around over the upper surfaces of the bars and fastened by a thumb-screw 38 or other device to the other frame side. In case any of the pins 24 or 27 should prove inadequate to hold the leather because of the bending of the pins or tearing of the leather they may be reinforced by nails driven through the leather into the board 13 in front of the holder, as shown at 38 in Figs. 1 and 3. The nails can be extracted with a claw-hammer or like device, and when it is desired to remove the leather it maybe pulled 0d the pins 24 and 27 without releasing the clamp-bar 37.

In the operation of stretching the leather it is desirable to have its body portion lie on cross-bars 39, that rest and may be shifted on the side pieces 1 and which the operator may move from time to time toward or away from the ends or to inclined positions, (indicated by dotted lines in Fig. 1,) as in his judgment may be desirable to compensate for unequal stretching of the edges or other portions of the leather.

In preparing leather for belting it is desirable to stretch the softer and more yielding portions to a greater extent than the harder and less yielding portions. This result may ICC be reached by connecting and operating different holders ofathe series inproper so quencethat is, the holders for the softer and more yielding portion should be first connectw ed and that portion given an initial' stretching before other holders are put to work-and other portions of varying consistency successively engaged and stretched. As illustrated in Figs. 1 and 3,-the holders shown as in engagement with the shortest portions of the leather, which are portions nearest the sides of the hide and are softer, more yielding, and capable of being stretched to a greater ex tent without injury to the fiber than adjoining or other portions,may be first put in service and those portions stretched until of about the same tenacity or ability to resist stress as the portions that are contiguous to them, and the other holders may then be put to work in proper sequence tostretch different longitudinal sections of the leather to monly employed in leather-stretching machines and that it is thereby better fitted for use in the manufacture of belting.

I am not aware that it has heretofore been proposed to employ in connection with a stretcher-head aseries of independentleatherholding devices adapted to engage only short marginal portions of a bodyof leather and coupling devices to which-the holders are pivoted to turn freely in lateral direction at all times, the stretcher-head and coupling devices being provided with cooperating means whereby the latter are supported by and connected to and are longitudinally and laterally adjustable upon the head. Therefore I do not wish to limit my claims to the-specific character, form, or arrangement of the devices shown and described, for the same results may be accomplished in the same way by such modifications of the devicesas would suggest themselves to the skilled constructor.

The modification of the devices illustrated in Fig. 6 of the drawings is reserved to be specifically claimed in a pending divisional application, No. 42,469, filed January 8, 1901, and the means disclosed for securing the straight end of theleather to the stretcherhead is part of thesubject-matter of my pending application, No. 738,820, filed December 1,1899, and is reserved to be claimed therein. The subject-matter of invention herein disclosed and 'not claimed relativeto the means for varying the point of pivotal connection of the holder to the coupling device conformably to the direction of tension of the leather is reserved to be claimed in my pending application, No. 10,128, filed March 26, 1900.

-What'I claim, and desire to secure by Letters Patent, is-

1. I In a stretching mechanism, the combination with a stretching-frame, of a stretcher head provided with serrations on its surface, a series of independent leather-holders hav-- ing means for attachment to short marginal portions of the'leather, and a corresponding series of coupling devices loosely pivoted to the holders and permitting them to swing freely under tension, the coupling devices being adapted to be adjusted laterally and longitudinally upon and to engage such serrated surface, and means for locking said coupling devices in their adjusted positions on said surface, substantially as set forth.

2. The combination with a stretcher-head provided with transverse's'errations, of a "series of leather-holders adapted to engage short marginal portions of the leather, and a corresponding series of coupling'devices freely pi voted to the holders and provided with teeth, whereby the coupling devices may be adjusted laterally and longitudinally and connected with the serrations on the stretcherhead, substantially as set forth.

3. In combination in a leather=stretching mechanism, a frame; a sliding and a fi'x'ed head therein; leather holders, comprising bodies provided withmeans for engaging the leather, and pivotally-conne'cted shanks capable of independent adjustment and provided with teeth; and serrations on the stretcherhead for engaging said teeth, substantially as set forth.

LIn combination in a leather-stretching mechanism, a frame; a sliding'and a fixed head therein; leather-holders, comprising bodies provided with means for engaging the leather,and pivotally-connected shanks capable of independent adjustment and provided with teeth serrations on the stretcher-head for engaging said teeth; and means for hold ing the shanks in place thereon,- substantially as set'forth. V 1

In testimony. whereof I have hereunto 'set my hand this 9th day of January, 1900.

IIO

JOHN CALDWELL.

In presence of- F. H. GEORGE, P. H. GUNOKEL. 

